Improvement in boom jacks or elevators



R. BfCONDON.

Improvement in Boom-Jack or Elevator.

' NVO. 131,742. Patented Octn 1872.

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`'RUFUS B. GONDON, OF BELFAST, MAINE.

lMPRVEMENT IN BOOM yJACKS OR ELEVATORS.

Specification forming'partof Letters Patent YNo. 131,742, dated October 1,1872.

To all whom it may concern:

Be it known that I, BUFUS B. CONDON, of Belfast, of the county of Waldo and State of Maine, have invented a new and useful Boom Jack or Elevator; and do hereby declare the same to be fully described in the following specification and represented' in the accompanying drawing, of which- Figure l is Va bottom view; Fig. 2, a side elevation; Fig. 4, an edge view; vand Fig. 3, a

longitudinal section of it.

The purpose of the said device is to elevate and support the boom of a navigable vessel. It consists of a Wheel-carriage, A, and a vibratory arm or notched toggle, B,- the latter being pivoted to the carriage andthe wholebeing arrangedv and constructed substantially as shown in the drawing.

The carriage is'forined of two circular segmental-shaped side pieces, a a, arranged at a suitable distance apart and connected by two transverserings, b b. Two Wheels or rollers, c c, disposed between the side pieces a a, in manner as shown, are to turn freely on pins or rods d d going from one to the other of the side pieces and supported by both. The notched toggle B, pivoted to the carriage, as shown 'at e, is provided atits upper end with a notch, f, to receive the boom.

When a boom is to be raised the jack, with the toggle inclined from the vertical so as to receive the boom in the crotch or notch f, is to be moved transversely against the boom.

On continuing to press or draw the carriage forward the boom will be raised until the toggle may assume a Vertical position, in which 

